1. Field of the Invention
The present invention relates to a silver halide photographic light-sensitive material having a dyed hydrophilic colloidal layer or layers. In particular, it is concerned with a silver halide photographic light-sensitive material containing a hydrophilic colloidal layer or layers dyed with a dye which does not detrimentally influence the spectral sensitivity of the photographic emulsion layers.
2. Description of the Prior Art
With silver halide photographic light-sensitive materials, photographic emulsion layers and like layers are often dyed for the purpose of absorbing light in a specific wavelength region.
Where it is necessary to control the spectral composition of light incident upon photographic emulsion layers, a colored layer is usually provided on a side farther from the support than the photographic emulsion layers in a photographic light-sensitive material. Such a colored layer is called a filter layer. Where a plurality of photographic emulsion layers are present as in a multi-layer color light-sensitive material, such a filter layer is sometimes interposed between photographic emulsion layers.
Where the intention is to prevent images from becoming indistinct, i.e., halation, due to light scattered during or after transmission through the photographic emulsion layers and reflected at the interface between an emulsion layer and a support or at the opposite surface of the light-sensitive material to the emulsion layers and again striking the photographic emulsion layers, a colored layer is provided between a photographic emulsion layer and a support or on an opposite side of the support to the photographic emulsion layers. Such colored layers are called antihalation layers. Where a plurality of photographic emulsion layers are present as in a multi-layer color light-sensitive material, the antihalation layer is in some cases interposed between these photographic emulsion layers.
In order to prevent a reduction in image sharpness due to the scattering of light in photographic emulsion layers (this phenomenon being usually called irradiation), the photographic emulsion layers are also colored.
These layers to be colored, in many cases, comprise a hydrophilic colloid, and hence water-soluble dyes are usually incorporated in these layers to color the layers. Dyes to be used for this purpose must satisfy the following criteria as well as possess an appropriate spectral absorption in accordance with the end-use of the photographic light-sensitive material:
1. The dyes should be chemically photographically inert, that is, they should not chemically detrimentally influence the properties of silver halide photographic emulsion layers, such as cause a reduction in sensitivity, cause the latent image to fade or cause fog.
2. The dyes should be capable of being decolored or dissolved out into a processing solution or into a wash water during the photographic processing steps, and harmful residual color of the dye should not remain in the processed photographic light-sensitive material.
Of the above-described two criteria, the first criterion of being chemically photographically inert should be satisfied with respect to properties in spectrally sensitized regions as well as in the intrinsic sensitivity region of silver halide, i.e., the wavelength region of intrinsic absorption of silver halide. That is,
i. the dyes should not spectrally sensitize photographic emulsions which have not been spectrally sensitized (spectral sensitization would make the use of a safe light difficult in handling light-sensitive materials in a dark room),
ii. the dyes should not reduce the spectral sensitization efficiency of a spectrally sensitized photographic emulsion,
iii. the dyes should not shift the wavelength of spectral sensitization maximum or not produce a new spectral sensitization maximum, and
iv. the dyes should not affect the spectral sensitization characteristics, for example, widen or narrow the spectrally sensitized region.
As the water-soluble dyes useful for dyeing hydrophilic colloidal layers of a photographic light-sensitive material for the above-described objects, many dyes are known. For example, oxonol dyes having pyrazolone nuclei, represented by the dyes described in British Pat. No. 506,385; oxonol dyes having barbituric acid nuclei, represented by the dyes described in U.S. Pat. No. 3,247,127; other oxonol dyes described in U.S. Pat. Nos. 2,533,472, 3,379,533, British Pat. No. 1,278,621; hemioxonol dyes represented by the dyes described in British Pat. No. 584,609; styryl dyes represented by the dyes described in U.S. Pat. No. 2,298,733; merocyanine dyes represented by the dyes described in British Pat. No. 1,153,341; cyanine dyes represented by the dyes described in U.S. Pat. No. 2,843,486; and the like, are illustrative.
Of these, symmetrical oxonol dyes having two pyrazolone nuclei have been used as useful dyes for dyeing layers of a light-sensitive material since they can be decolored in a developer containing sulfite, they affect the photographic properties of photographic emulsions only to a slight extent, and they can be synthesized in a good yield with high purity.
However, many of the dyes belonging to this class spectrally sensitize photographic emulsions (which have not been spectrally sensitized). For example, a dye having the following structural formula: ##SPC1##
can spectrally sensitize a pure silver bromide emulsion or a silver bromoiodide emulsion have a low iodide content to produce a spectrally sensitized region at around 590 nm which is quite different from their spectral absorption region. Also, many of them detrimentally influence the spectral sensitivity characteristic of a silver halide emulsion sensitized with a sensitizing dye, regardless of the effect on their spectral absorption. That is, they not only reduce the sensitization in the wavelength region of main spectral sensitization, but produce a new spectral sensitivity as well in a wavelength region where spectral sensitivity is not desired. For example, when the aforesaid dye (structural formula A) is added to a silver bromoiodide emulsion layer (containing 1 mol% iodide) spectrally sensitized with 2-[(3-ethyl-4,5-diphenyl-thiazolyl)methylidene]-5-[2-(3-ethylbenzothiazoly lidene)ethylidene]-3-methyl-thiazolidin-4-one or to an adjacent gelation layer, spectral sensitization at the main sensitization wavelength (640 nm) is reduced and, in addition, a new spectral sensitization appears in the wavelength region of 500 to 520 nm. Production of spectral sensitivity due to the presence of such a dye in a photographic emulsion which has not been spectrally sensitized or production of a new spectral sensitization in a spectrally sensitized photographic emulsion results in a photographic light-sensitive material having various disadvantages. Firstly, it greatly degrades the adaptability of a photographic light-sensitive material to a safe light. That is, the wavelength region capable of being used for safe light illumination is extremely limited or the conditions permitting the handling of a photographic light-sensitive material under a safe light (e.g., the closest distance from the light source, the longest handling time, etc.) are extremely restricted. Also, with a multi-layer color light-sensitive material, the spectral sensitivity of one emulsion layer overlaps that of other layers to a greater extent. Thus, color separation between each layer and, therefore, color reproduction of the color image are deteriorated.